7,000 migrants arrested in a day: The latest on the U.S.-Mexico border crisis

A migrant carries bags towards the US border fence from Ciudad Juarez, Mexico, on Wednesday, December 27. (Christian Chavez/AP)

Eagle Pass, Texas -

The crisis at the U.S.-Mexico border continues, with a migrant surge overwhelming authorities and border towns and other U.S. cities. Here are some of the latest developments:

DOJ says it will sue Texas over its new law

The Department of Justice has threatened to sue Texas over its new immigration law in a letter Thursday, according to a copy of the letter obtained by CNN. The threat marks the latest escalation between President Joe Biden and Republican Gov. Greg Abbott over the handling of the U.S.-Mexico border.

Earlier this month, Abbott signed Senate Bill 4 into law, giving local law enforcement the power to arrest migrants and empowering judges to remove migrants from the U.S. The measure is expected to take effect in March.

The White House slammed the new law, calling it "incredibly extreme."

In a letter to Abbott, the DOJ argued the measure is "preempted and violates the U.S. Constitution" and risks interfering with the federal government’s ability to enforce immigration law.

"Accordingly, the United States intends to file suit to enjoin the enforcement of SB 4 unless Texas agrees to refrain from enforcing the law," the letter, signed by Principal Deputy Assistant Attorney General Brian Boynton, states. "The United States is committed to both securing the border and ensuring the processing of noncitizens consistent with the Immigration and Nationality Act (INA). SB 4 is contrary to these goals."

Abbott slammed the Justice Department’s letter later Thursday and accused President Joe Biden of "destroying America."

"The Biden Admin. not only refuses to enforce current U.S. immigration laws, they now want to stop Texas from enforcing laws against illegal immigration," Abbott said in a post on X. "I’ve never seen such hostility to the rule of law in America."

Thursday’s legal threat comes after DOJ sued Texas over its use of floating barriers in the Rio Grande. That lawsuit is still making its way through the courts.

7,000 arrests in a day mark a decrease

Border authorities apprehended more than 7,000 migrants along the U.S.-Mexico border on Wednesday, according to a Homeland Security official.

Wednesday’s arrests are still lower than earlier this month – when daily apprehensions surpassed 10,000 – and reflects some relief for border authorities. There has been a "pretty significant reduction in border crossings" in recent days, a senior administration official said Wednesday.

In early December, the seven-day average of daily encounters hovered around 9,600 – a jump from late November, when that average stood at 6,800.

U.S. and Mexican officials described high-level talks Wednesday as "productive" as Mexico moves to double down on immigration enforcement and crack down on human smugglers.

About 2,000 border arrests Wednesday took place in the Del Rio Sector, according to a law enforcement source.

The same source said total apprehensions Monday were about 2,000, a drop from the 3,000 daily average number of migrant apprehensions last week.

The Del Rio Sector includes Eagle Pass, Texas, which had thousands of migrants waiting outside to be transported for immigration processing last week.

Mexican officials will visit Washington

Mexican and U.S. officials will meet in Washington next month to discuss curbing the influx of migrants into the U.S., according to the U.S. National Security Council.

The visit will come after this week’s high-level U.S. delegation visit to Mexico City, which included Secretary of State Antony Blinken and Homeland Security Secretary Alejandro Mayorkas.

A National Security Council spokesperson called the trip "productive" and said Mexican President Andrés Manuel López Obrador “has taken significant new enforcement actions” when it comes to migration.

Mexican Secretary of Foreign Affairs Alicia Barcena told reporters the talks also covered the importance of the economic relationship between the US and Mexico, as well as the root causes of migration, such as poverty, inequality, violence and family reunification, according to a recording provided to CNN by Mexico’s foreign ministry.

U.S. officials said Mexico shared plans to crack down on migrant smugglers, which is contributing to the recent increase at the border.

Mexico has also taken a leadership role on "conducting humane border management, including repatriations," a U.S. senior administration official said, and that more repatriations were conducted this year than ever before.

The U.S. has historically leaned on Mexico to act as a buffer and stem the flow of migrants journeying to the US southern border. But Mexico, like the US, faces similar difficulties as the number of migrants crossing into its country overwhelms its limited resources.

Many migrants coming from the Mexican side of the border are from Central and South America as well as the Caribbean, Cuba and Haiti.

Immigration has been a political vulnerability for Biden, who has faced fierce criticism from Republicans and even some members of his own party for the situation at the US-Mexico border.

U.S. officials acknowledge more work needs to be done by both countries.

“We continue to address the root causes and build on legal pathways that incentivize orderly migration and enforcement of our laws,” a National Security Council official said.

The January meetings will “assess progress and decide what more can be done,” the National Security Council official said.